• Applied Chemistry for Engineering
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• v.9 no.6
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• pp.803-810
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• 1998

We have studied the catalytic combustion of soot particulate over perovskite-type oxides prepared by malic acid method. The catalysts were modified to enhance the activity by substitution of metal into A or B site of perovskite oxide. In addition, the reaction conditions, such as temperature, $O_2$ concentration, space velocity have been studied. The effect of $SO_2$ pretreatment and water introduced into reactants were also examined. In the $LaCoO_3$ catalyst, the partial substitution of alkali metals into A site enhanced the catalytic activity in the combustion of soot particulate and the activity was shown in the order : Cs>K>Na; In the $La_{0.6}Cs_{0.4}CoO_3 $; catalyst, the substitution of Fe or Mn showed no effect on the ignition temperature. The ignition temperature decreased with increasing $O_2$ concentration and contact time. The introduction of water into reactants feed decreased the ignition temperature and the pretreatment of $SO_2$ showed no effect on the catalytic activity.

• Applied Chemistry for Engineering
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• v.10 no.3
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• pp.407-414
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• 1999

We have studied the reduction of NO by CO over perovskite-type oxides prepared by malic and method. The catalysts were modified to enhance the activity by substitution of metal into A or B site of perovskite oxides. In the $LaCoO_3$ type catalyst, the partial substitution of Sr into A site enhanced the catalytic activity on the conversion of NO at less than $350^{\circ}C$. In the $La_{0.6}Sr_{0.4}Co_{1-x}Fe_xO_3$ catalyst, the partial substitution of Fe or Mn into B site enhanced the conversion of NO, but excess amount of Fe decreased the conversion of NO. In addition, $La_{0.6}Sr_{0.4}Co_{0.8}Fe_{0.2}O_3$ mixed with $SnO_2$ or $MnO_2$ showed the synergy effect on the reduction of NO. The introduction of water into reactants feed decreased the catalytic activity but the deactivation was shown to be reversible. The introduction of $SO_2$ into reactants feed also decreased the catalytic activity.

• Applied Biological Chemistry
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• v.39 no.4
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• pp.327-331
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• 1996

This experiment was conducted to establish the efficient extraction condition for anthocyanin and tannin pigments contained in rice bran of colored rices. Efficiency of the pigment extraction was maximum when the concentration of mired solvent of methanol(3) : ethanol(7) was 70%. In purple rite(anthocyanin pigment), ‘Kilimheugmi’, 80% ethanol containing 0.5% malic acid showed the highest extraction efficiency and stability with a maximum absorbance wavelength$(\lambda_{max})$ at 538 nm. In red rice(tannin pigment), ‘Jagwangdo’, 80% ethanol containing 0.01% citric acid showed the highest extraction efficiency and stability with a maximum absorbance wavelength$(\lambda_{max})$ at 456 nm. The relative optical density of the pigments increased until the solvent temperature was reached at $70^{\circ}C$, but drastically decreased over at $90^{\circ}C$ due to color change. The higher amount of the pigment was ertracted from the longer shaking time of the solvent. Ten minutes was enough for the grinding time of rite bran in solvent. Supernatant of the pigment extractives after one day storage at $4^{\circ}C$ in dark chamber revealed higher optical density than the filtration of the pigment extractives.

• Applied Chemistry for Engineering
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• v.7 no.3
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• pp.543-553
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• 1996

Oxygen reduction in an alkaline fuel cell was studied by using perovskite type oxides as an oxygen electrode catalyst. The high surface area catalysts were prepared by malic acid method and had a formula of $La_{0.6}Sr_{0.4}Co_{1-x}Fe_xO_3$(x=0.00, 0.01, 0.10, 0.20, 0.35 and 0.50). From the result of XRD pattern and specific surface area due to the amount of Fe substitution and the consumption of ammonia-water, the complex formation of Fe ion with $NH_3$ was the main factor for both the phase stability of perovskite and the increase of specific surface area. Multi-step calcination was necessary to give a single phase of perovskite in catalyst precursor. The crystal structure of the catalysts was simple cubic perovskite, which was verified from the XRD patterns of the catalysts. The activity of oxygen reduction was monitored by the techniques of cyclic voltammetry, static voltage-current method, and current interruption method. The activity(current density) of oxygen reduction showed its minimum at x=0.01 and its maximum between 0.20 and 0.35 of x-value in $La_{0.6}Sr_{0.4}Co_{1-x}Fe_xO_3$. This tendency was independent of the change of surface area.

• Applied Biological Chemistry
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• v.39 no.5
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• pp.338-342
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• 1996

Fruit of Lycium chinense Miller was known to Korean as traditional medicine that has effective components for strengtherning function of human body, especially liver. To study characteristics of the wine and Yakju made by fruit Lycium chinense Miller, general components such as organic acid, methanol, ester, fusel oil and $SO_2$ were analyzed after storing them for 10 and 20 days at $20^{\circ}C\;and\;30^{\circ}C$, respectively. Organic acid contents of the wine were mainly lactic, malic, tartaric and acetic acid. Ester and fusel oil contents of the wine were $4.0{\sim}5.0\;mg%$ and $12{\sim}30\;mg%$, respectively, and the values were smaller than those of the Yakju. Methanol content of the wine was $25{\sim}27\;mg%$. Storage temperature in terms of the quality of the wine and Yakju was better in $20^{\circ}C\;than\;30^{\circ}C$. Treatment of the wine and Yakju either by adding 100 ppm of $SO_2$ or heating at $60^{\circ}C$ for 30 min was better in quality than control for storage.

• Journal of the Korean Society of Food Culture
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• v.5 no.3
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• pp.301-311
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• 1990

The agriculture of Korea was begun in the neolithic era partly and generalized around 4,000 B.C. Discovery of acorn and stoneworks used in agriculture in neolithic era in 8,000 B.C to 6,000 B.C suggests that prehistoric ancestors of Korean night use acorn, hazel-nuts, and haws, etc. as foods. Cultivation of chestnuts, peaches, plums, pears, and japanese apricots was found in Mahan, the tribal states, and in the period of three kingdoms and Balhae dynasty too. In the period of Koryo, pears, plums, japanese apricots, pine nuts, apricots, grapes, jujubes, gingko nuts, oranges, and citrons were cultivated and used in diet. Sejongsilrokjiriji(1454), a geography of the early chosun, and Sinjungtonggukyojisungnam(1492) show that they cultivated almost all fruits we are now cultivating such as hazel-nuts, haws, nutmeg nut, and so on. Loquats seem to be brought in the early chosun era and figs around 16th century. Pecans, sweet cherries were brought around 1,900 and recently tropical fruits like kiwis were brought in and used in a large scale. In addition, Some fruits were used in medical treatments. Fruits increase the pleasure of the diet and sometimes they are used as a measure of a standard of living. Fruits have been improved and used for a long time, their status in our diet will be maintained resolutly.